It is known that a ceramic material useful as an abrasive can be made from electric arc furnace dust. Thus, it is disclosed in U.S. Pat. No. 5,738,694 of George W. Ford, Jr., "EAF dust has also been processed by blending with silicate materials, such as silica sand, clay, or cullet, and heated in a furnace to form a vitrified ceramic product. The ceramic is useful as an abrasive . . . ."
The Ford patent does not disclose the physical and chemical properties of the abrasive material allegedly made by its process. However, in general, a commercially suitable abrasive with satisfactory hardness properties is not produced by this prior art process.
In fact, the abrasive produced by the process of the Ford patent apparently has little commercial value. Ford teaches that, although "The ceramic is useful as an abrasive, and the EAF dust is rendered nonhazardous," ". . . the valuable metals contained in the dust are not recovered" (see lines 31-37 of Column 3 of this patent). Clearly, the abrasive material made by the process of the Ford patent is not worth as much as its metal content.
It is an object of this invention to provide an abrasive material made from electric arc furnace dust which has a substantial commercial value which is greater than the value of the metals in the material.
It is another object of this invention to provide a magnetic abrasive material which can readily be collected by magnetic collection means.